[Oracle10g]-关于表空间的更名

王朝oracle·作者佚名  2008-05-19
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简单介绍

在 Oracle 10g 以前的版本,更改表空间名字是几乎不可能的事情,除非删除,重新创建,大费周章。Oracle 10g 新添加了一项更改表空间名字的功能,使得更改表空间名字瞬间即可完成。是个较为人性化的功能。

SQL COL FILE_NAME format a70

SQL SET linesize 120

SQL SET pagesize 99

SQL COL TABLESPACE_NAME format a10

SQL

SQL SELECT file_name, tablespace_name FROM dba_data_files;

FILE_NAME

TABLESPACE

---------------------------------------------------------------------- ----------

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/users01.dbf

USERS

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf

SYSAUX

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf

UNDOTBS1

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf

SYSTEM

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf

EXAMPLE

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf

FOO

6 rows selected.

该命令的语法很简单:

ALTER TABLESPACE tablespacename RENAME TO newtablespacename;

tablespacename 和newtablespacename 分别对应原来的表空间名字和更改后的表空间名字:

实战演练

注意:在操作前后都请做好控制文件的备份工作

SQLALTER TABLESPACE foo RENAME TO test;

Tablespace altered.

SQL SELECT file_name, tablespace_name FROM dba_data_files;

FILE_NAME

TABLESPACE

---------------------------------------------------------------------- ----------

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/users01.dbf

USERS

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf

SYSAUX

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf

UNDOTBS1

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf

SYSTEM

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf

EXAMPLE

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf

TEST

因为 system 和 sysaux 这两个表空间的特殊性,是不可以更名的:

SQL ALTER TABLESPACE system RENAME TO mysystem;

ALTER TABLESPACE system RENAME TO mysystem

*

ERROR at line 1:

ORA-00712: cannot rename system tablespace

SQL ALTER TABLESPACE sysaux RENAME TO mysysaux;

ALTER TABLESPACE sysaux RENAME TO mysysaux

*

ERROR at line 1:

ORA-13502: Cannot rename SYSAUX tablespace

可以对 undo tablespace 重新命名,如果使用的是 spfile ,而不是 pfile, Oracle 会自动对 spfile 中的 undo_tablespace 进行更改(不过要在数据库重新启动之后才可以观察到), 如果使用的是 pfile ,要对其进行手工更改。我们看看 spfile 的变化情况:

SQL ALTER tablespace undotbs1 RENAME TO undotbs;

Tablespace altered.

SQL

SQL show parameter pfile

NAME

TYPE

VALUE

------------------------------------ ----------- ------------------------------

spfile

string

/u01/app/oracle/product/10.1.0

/db_1/dbs/spfileTEST.ora

SQL show parameters undo

NAME

TYPE

VALUE

------------------------------------ ----------- ------------------------------

undo_management

string

AUTO

undo_retention

integer

900

undo_tablespace

string

UNDOTBS1

SQL shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SQL startup

ORACLE instance started.

Total System Global Area

180355072 bytes

Fixed Size

777996 bytes

Variable Size

128983284 bytes

Database Buffers

50331648 bytes

Redo Buffers

262144 bytes

Database mounted.

Database opened.

SQL show parameters undo

NAME

TYPE

VALUE

------------------------------------ ----------- ------------------------------

undo_management

string

AUTO

undo_retention

integer

900

undo_tablespace

string

UNDOTBS

SQL

对脱机表空间的更名是不允许的:

SQL ALTER TABLESPACE TEST OFFLINE;

Tablespace altered.

SQL ALTER TABLESPACE test RENAME TO testoffline;

ALTER TABLESPACE test RENAME TO testoffline

*

ERROR at line 1:

ORA-01135: file 6 accessed for DML/query is offline

ORA-01110: data file 6:

'/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf'

给出的提示信息很有参考价值:更名操作是要对表空间进行 DML/query 操作的,表空间offline的话,则不可以。

那么如果表空间是只读的会怎么样呢?

SQL ALTER TABLESPACE TEST ONLINE;

Tablespace altered.

SQL ALTER TABLESPACE TEST READ ONLY;

Tablespace altered.

SQL ALTER TABLESPACE test RENAME TO testreadonly;

Tablespace altered.

SQL list

1* SELECT file_name, tablespace_name FROM dba_data_files

SQL /

FILE_NAME

TABLESPACE

---------------------------------------------------------------------- ----------

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/users01.dbf

USERS

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/sysaux01.dbf

SYSAUX

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/undotbs01.dbf

UNDOTBS

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/system01.dbf

SYSTEM

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/example01.dbf

EXAMPLE

/u01/app/oracle/product/10.1.0/db_1/oradata/TEST/foo1.dbf

TESTREADONLY

6 rows selected.

SQL

看来数据字典已经更新,不过Oracle会向alert_SID.log 中写入类似如下的日志:

ALTER TABLESPACE test RENAME TO testreadonly

Sat Nov 13 16:15:21 2004

Tablespace 'TEST' is renamed to 'TESTREADONLY'.

Tablespace name change is not propagated to file headersbecause the tablespace is read only.

Completed: ALTER TABLESPACE test RENAME TO testreadonly

注意Log里有个细微的小Bug:headersbecause。这是两个词,应该空开的 :-)

限制条件

应用这个特性有个主要的限制条件:COMPATIBLE 初始化参数要求为 10.0 或者更高才可以

 
 
 
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